Rotary internal combustion engine

ABSTRACT

A rotary-piston internal combustion engine having an annular compression cylinder and a separate annular combustion cylinder with one or more passages interconnecting the two cylinders and with valves dividing the compression cylinder into intake and compression chambers and the combustion cylinder into combustion and exhaust chambers. At least one piston is mounted within each cylinder and is rigidly mounted on a drive shaft common to the pistons for both cylinders, such that it revolves within its corresponding cylinder. The piston in the compression cylinder compresses a charge of gaseous fuel mixture into the passage between the cylinders, from which the gases expand into the combustion cylinder with combustion taking place just as the trailing end of the combustion piston passes the outlet from the pressure passage. In addition to forming the chambers within the cylinders, the valves are driven by the pistons into passageclosing relation with the inlet and outlet for the pressure passage, such inlet and outlet being within the walls of the compression and combustion cylinders, respectively. Movement of such valve into its chamber-forming position takes place as the trailing end of the corresponding piston moves downstream, permitting the valve to be driven out of its passage-closing position and back into its chamber-forming position.

United States Patent [1911 Blaszczynski [111 3,818,886 [4 June 25, 19741 ROTARY INTERNAL COMBUSTION ENGINE [76] Inventor: ZdzislawBlaszczynski, 174

Pleasant View Rd., Thomaston, Conn. 06787 [22] Filedz May 4, 1973 [21]App]. No.: 357,350

Related 0.8. Application Data [63] Continuation'inpart of Set. No.230,783, March 1,

1972, abandoned.

[52] 11.5. C1. 123/841, 123/825 [51] Int. Cl. F02b 53/08 [58] Field ofSearch 123/8.l7, 8.23, 8.25, 8.41

[56] References Cited UNITED STATES PATENTS 1,180,747 4/1916 Whitel23/8.41 1,186,879 6/1916 Brush 1,235,786 8/1917 Fleming... 1,366,9192/1921 Marvin .1 1,405,326 1/1922 Powell 1,810,082 6/1931 Marvin1,916,318 7/1933 Huber 2,289,342 7/1942 Canfield.... 2,933,505 5/1960Quarter 123/825 3,361,119 1/1968 Floxley-Conolly 123/823 2.196.675 4/1940 Humrichouse 123/841 Primary E.\'aminerC. J. Husar Attorney, Agent,or Firm-Steward & Steward [57] ABSTRACT A rotary-piston internalcombustion engine having an annular compression cylinder and a separateannular combustion cylinder with one or :more passages interconnectingthe two cylinders and with valves dividing the compression cylinder intointake and compression chambers and the combustion cylinder into combustion and exhaust chambers. At least one piston is mounted within eachcylinder and is rigidly mounted on a drive shaft common to the pistonsfor both cylinders, such that it revolves within its correspondingcylinder. The piston in thecompression cylinder compresses a charge ofgaseous fuel mixture into the passage between the cylinders, from whichthe gases expand into the combustion cylinder with combustion takingplace just as the trailing end of the combustion piston passes theoutlet from the pressure passage. In addition to forming the chamberswithin the cylinders, the valves are driven by the pistons intopassageclosing relation with the inlet and outlet for the pressurepassage, such inlet and outlet being within the walls of the compressionand combustion cylinders, respectively. Movement of such valve into itschamber-forming position takes place as the trailing end of thecorresponding piston moves downstream, permitting the valve to be drivenout of its passage-closing position and back into its chamber-formingposition.

30 Claims, 24 Drawing Figures PATENTED JUN2 5 I974 SHEEF 1 (If 9PATENTEDJUNZSIHM FIG. 22

FIG. 23

FIG24 SHEET 9 BF 9 I re 1 ROTARY INTERNAL COMBUSTION ENGINE Thisapplication is a continuation-in-part of copending application Ser. No.230,783, tiled Mar. 1, 1972, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to improvements inrotarypiston internal combustion engines, and it relates moreparticularly to rotaryengines having companion pairs of compression andcombustion chambers or cylinders, in which a combustible mixture of fuelis compressed in one cylinder and then fed to the other where it ignitesand drives a rotor. Because of their two-cylinder arrangement, rotaryengines of this general type are sometimes referred to hereinafter asdual-cylinder engines.

Dual-cylinder engines have been provided with arcuately elongatedpistons, the leading end of each of which is located adjacent thetrailing end of a companion piston in the other cylinder in staggeredrelation to each other, so that a compressed charge in one cylinder maybe fed directly into a combustion chamber in the other. They have alsoemployed movable partitions for dividing each cylinder into separatechambers disposed circumferentially of each other. As each pistonreaches one of the partitions it cams that partition out of way so thatthe piston rotates uninterruptedly through the annular cylinder. Duringsuch rotation each partition is driven by some means, such as a heavyspring, back into its chamber-forming position as each of the pistonstravels downstream of it, thereby forming one chamber downstream,between it and the trailing end of the piston, and a second chamberupstream of it.

For example, the compression cylinder may be provided with one or morepartitions, each of which forms a suction or intake chamber downstreamand a compression chamber upstream. Similarly, the combustion cylinderis provided with a corresponding number of partitions, dividing it intocombustion and exhaust chambers. The two cylinders are interconnected byone or more passages into which a combustible air-fuel mixture is drivenby the compression piston. Each of such passages discharges into thecombustion cylinder downstream of one of the chamber-forming partitionswhere the fuel is ignited and, as it expands, drives the combustionpiston and therefore the rotor. The spent exhaust gases are thendischarged through exhaust ports located upstream of each partition inthe combustion cylinder.

A disadvantage of such prior dual-cylinder rotary engines is that thecombustion and compression chambersare difficult to seal against leakageto the atmosphere, as well as from one chamber to another within theengine. One of the reasons for this is that the transfer of thecompressed fuel mixture from the compression cylinder to the combustioncylinder has usually been effected only by means of chamber-formingvalves within the cylinders, these valves having the sole function ofdividing each of the cylinders into chambers disposed annularly of eachcylinder. It has therefore been necessary up to now to providecomplicated, externally actuated valving mechanisms, which are not onlydifficult to maintain, but in some cases act so slowly that they greatlyreduce the output of the engine.

An object of the present invention is to provide a simplified design ofdual-cylinder, rotary-piston engine,

SUMMARY OF THE INVENTION A rotary engine in which the present inventionis employed includes one or more arcuate compression pistons whichrevolve within a cylindrical compression space, together with acorresponding number of arcuate combustion pistons rigidly mounted onthe same rotor with the compression piston, but revolving within aseparate cylindrical space in which combustion takes place. Each pistonextends lengthwise an equal dis tance in terms of degrees of arc alongits path of travel with the compression pistons disposed substantiallyend-to-end and in staggered relation with the combustion pistons, sothat together they extend substantially continuously around the completecircumference of the rotor. One or more pressure passages disposedcircumferentially of each other interconnect the compression andcombustion cylinders, each passage having an inlet from the compressioncylinder for receiving the fuel mixture as it is compressed by thecompression piston, and an outlet to the combustion cylinder fordischarging the compressed fuel into the combustion cylinder. Acompression valve is mounted adjacent the compression cylinder near theinlet to each pressure package, such that it can move into achamber-forming position within the compression cylinder downstream ofthe inlet, in order to divide such cylinder into a compression chamberupstream and an intake chamber downstream. A combustion valve issimilarly mounted adjacent the combustion cylinder near the outlet foreach pressure passage, each combustion valve being movable into achamber-forming position within the combustion cylinder upstream of theoutlet so that this cylinder is in turn divided circumferentially intoan exhaust chamber upstream of such valve and a combustion chamberdownstream of it.

The invention basically resides in disposing both the compression valveand the combustion valve at each pressure passage so that when each ismoved out of its chamber-forming position, it closes the respectiveinlet or outlet to the pressure passage. Each valve therefore has twofunctions: one to divide each annular cylinder into separate chambers,the other to close off the pressure passage between the cylinders. Thus,as the leading end of the compression piston moves the compression valveat each pressure passage from its chamberforrning position, the samevalve moves into a passageclosing position with the inlet to thepressure passage. Similarly, as the combustion piston moves thecombustion valve at each pressure passage from its chamberformingposition, the combustion valve also moves to a passage-closing positionwith the outlet from the same pressure passage. Since the pistons aredisposed end-to-end in staggered relation within the two cylinders, theleading end of a piston in one cylinder is located at the opening toeach pressure passage when the trailing end of a piston in the othercylinder is adjacent the other opening to the same passage.Consequently, the two valves at each pressure passage are operated inopposite directions and substantially at the same time as the ends ofthe two co-operating pistons in the two cylinders move into and out ofengagement with them.

Thus, as the trailing end of the compression piston passes the inlet toeach pressure passage, the compression valve at this location moves fromits passage closing position to its chamber-forming position.Simultaneously therewith the leading end of the combustion piston camsthe combustion valve at the same location out of its chamber-formingposition and into its passage-closing position. The fuel mixture in thecompression chamber is therefore compressed by the next compressionpiston into the pressure passage where it is trapped by the combustionvalve. Then, as the leading end of the compression piston moves thecompression valve back into its passage-closing position, the trailingend of the combustion piston releases the combustion valve, which isdriven instantly into its chamberforming position as ignition of thefuel mixture takes place.

The advantage in this arrangement is that the openings, to and from thepressure passage are positively controlled by the pistons themselves, sothat each pressure passage becomes in effect an integral part of thecompression chamber during the compression phase of each cycle and,alternatively, an integral part of the combustion chamber during thecombustion phase of each cycle. This cooperative interaction of thepistons and valves at each pressure passage, which will be more clearlyunderstood from the detailed disclosure hereinafter, eliminates the needfor complicated valveactuating devices, which can breakdown or requiremaintenance and, which in any event are inherently too slow-acting toprevent leakage. In addition, throughout the entire combustion stroke,the expanding gases urge the seals in the valves into sealing engagementwith fixed valve seats, thereby overcoming the problem usuallyencountered in rotary internal-combustion engines of leakage betweencontinually moving parts.

It will be noted that more than one piston may be provided in eachcylinder, as long as there is a corresponding number of pistons in thecompanion cylinder, and as long as such pistons are disposed at equalintervals within each cylinder. In addition, while each cylinder isordinarily provided with a plurality of valves equally spaced from eachother, the valve arrangement of the present invention is capable of usein rotary engines having only one pressure passage between thecylinders. Such engines thereof employ only one compression valve andone combustion valve. Furthermore, in order to obtain the desiredhorsepower for a particular power plant, several pairs of compressionand combustion cylinders can be provided axially of the drive shaft, sothat a number of combustion pistons will be acting on the drive shaftsimultaneously.

For purposes of facilitating the disclosure, the first embodiment of theinvention disclosed in detail hereinafter is one in which companioncompression and combustion cylinders are disposed concentrically of eachother, that is, one within the other, rather than axially orside-by-side. Such an arrangement, moreover, has certain advantages thatcan not be achieved in any other way. However, it is believed that formost applications the cylinders should be disposed side-by-side, axiallyof the drive shaft as described in detail hereinafter in connection withanother form of the invention considered at the present invention toprovide advantages from a design standpoint, as well as in facilitatingthe manufacture and production of the engine.

DESCRIPTION OF PREFERRED EMBODIMENTS These and other objects andadvantages of the invention will be more apparent from the detaileddescription of certain preferred embodiments and of modifications shownor suggested by the accompanying drawings wherein:

FIG. I is a front view of a power plant incorporating one embodiment ofthe invention;

FIG. 2 is a longitudinal sectional view of the power plant shown in FIG.1, but on a larger scale and taken on the line 2-2 of FIGS. 1 and 3,looking in the direction of the arrows, and rotated clockwise through90;

FIG. is a vertical cross-section of the same shown on an intermediatescale and taken on line 3-3 of FIG. 2 looking in the direction of thearrows, portions of the annular pistons being broken away in order toexpose parts behind them FIG. 4 is a detailed sectional view taken onthe line 44 of FIGS. 1 and 3 but on a larger scale;

FIGS. 5 and 6 are enlarged detail views in vertical cross-sectionthrough one set of compression and combustion valves at one of thepressure passages and showing the actuation of the valves atsubstantially opposite ends of companion pistons;

FIG. 7 is a plan view on an enlarged scale of one of the compressionvalves;

FIG. 8 is a detail view in cross-section of the outer edge portion ofthe valve shown in FIG. 7 on a still larger scale, taken on line 8-8thereof, and showing portions of the cylinder and piston, with which itcooperates;

FIG. 9 is another detail of one of the side edge portions of the valveshown in FIG. 7 and taken in crosssection on the line 9-9;

FIG. 10 is a front view of the compression piston and piston-wheel shownon the same scale as in FIG. 3;

FIG. II is an enlarged detail view in cross-section of the compressionpiston taken on the line l1l1 of FIG. 10;

FIG. 12 is a partial view on an enlarged scale of the trailing endportion of the combustion piston-wheel;

FIG. 13 is a view similar to FIG. 12 of the leading end of thecombustion piston;

FIG. 14 is a cross-sectional view of the combustion piston taken on theline l4l4 of FIG. 12;

FIG. 15 is a view similar to FIG. 14 ofa slightly differ- I ent form ofcombustion piston and showing another manner of mounting it on itsmounting ring;

FIG. 16 is a more or less diagrammatic view of a second embodiment ofthe invention shown in longitudinal section through the center of thepower plant;

FIG. I7 is a vertical cross-section taken on the line I7l7 of FIG. 16;

FIG. 18 is a detailed sectional view on the line ll8l8 through the valveassemblage shown in FIG. 17;

FIG. 19 is a sectional view taken on the line 19--l9 of FIG. 18;

FIG. 20 is a pictorial representation of the valve and piston portion ofthe power plant shown in FIGS. 16-19 with the outer housing and one ofthe pistons removed in order to expose other parts and with portionsthereof shown broken away and in section;

FIG. 21 is a view similar to FIG. 19, but showing the positions of thepistons after the rotor has moved through one-half a revolution; and

FIGS. 22, 23 and 24 are diagrammatic views of still another valve andpiston arrangement embodying the invention, showing in sequence how theleading and trailing ends of the pistons co-operate to control theoperation of the valves in accordance with the invention.

CONCENTRIC CYLINDER ARRANGEMENT OF FIGS. ll-6 Referring moreparticularly to FIGS. 13, a cylindrical housing 10 encloses a powerplant having two sets of companion compression/combustion cylinders,indicated generally in FIG. 2 as sections A and B, each section beingidentical and consisting of a concentric, annular inner cylinder 12 andouter cylinder 14. Cylinders l2 and 14, are formed within a separatecylinder casing 16 for each of sections A and B. Cylinder casings 16, 16are ring-shaped and are rigidly mounted at their outer cylindricalsurfaces to the housing 10 at both ends thereof. Spacer rings 17, 17through which bolts 18 extend, are positioned at opposite ends of thepower plant between casings, 16, 16 and housing 10 in order to providean annular space 19 within the housing outward of cylinder casings 16,16, for a reason which will be more apparent hereinafter.

A drive shaft 20 is rotatably supported at each end axially withinhousing 10 on main bearings 22, 22, which are mounted centrally withincircular openings 23, 23 in casings 16, 16 adjacent the outer end-wallsthereof. Each pair of concentric, annular cylinders 12 and 14 comprisescompanion compression and combustion cylinders. In this particular case,the inner cylinder 12 of each pair is the compression cylinder, and theouter cylinder 14 is the combustion cylinder, but it will be appreciatedthat the reverse may be desirable in certain instances.

A rotor assembly indicated generally at 24 (FIG. 2) is mounted rigidlyon, and keyed to, drive shaft 20 by means of a key 25 for rotationtherewith. Rotor 24 consists of two piston-wheels 26, 26 mounted attheir centers in spaced, parallel relation to each other on shaft 20 andconcentric therewith, each piston-wheel 26 extending outward through aradially disposed, annular slot 27 in its respective cylinder casing 16into the corresponding one of its compression cylinders 12, 12. As willbe more apparent hereinafter, each slot 27 is formed in the innercylindrical wall of one of the ringshaped casings 16, 16 and providesaccess to the corresponding annular cylinder 12. As best viewed in FIGS.2 and 10, an arcuately elongated compression piston 28 is rigidlymounted at the periphery of each pistonwheel 26, 26. Pistons 28, 28 havethe same radius as the compression cylinders 12, 12 within which eachrotates, and each of pistons 28, 28 has a cross-sectional shape that isthe mirror image in cross-section of its cylinder 12 but slightlysmaller all around. Each of pistons 28 is positioned radially on itspiston-wheel 26 at a fixed distance from the axis of rotation equal toits radius of curvature, so that it completely clears the walls of thecylinder. The length of each piston 28, 28 at its outermost diameter isdesirably equal to one-half the circumference of its cylinder 12,

Interposed between the two piston-wheels 26, 26, as a unitary part ofrotor 24, is a central wheel-like memher 30, that is common to bothsections A and B of the engine. Wheel-member 30 is provided with a hub32, by which it is mounted on shaft 20 and to the opposite ends of whichare bolted piston-wheels 26, 26. The circular periphery of wheel-member30 projects radially outward of cylinder casings 16, 161 and is boltedinside a cylindrical drum or cross-head 341 midway between its edges 35,35. Drum 34, which surrounds portions of cylinder casings 16, I6, isdisposed concentrically of the housing 10 within the annular space 19between the inner surface of the engine housing and the outer surfacesof cylinder casings 16, 16. A series of recessed bolts 37 (FIG. 4)spaced circumferentially around wheel-member 30 rigidly fasten it to theinner surface of drum 34.

A pair of ring-shaped piston-wheels 38, 38 (FIGS. 2, 4, 12 and 13) arebolted to the inner surface of crosshead drum 34 adjacent its edges 35,35, so that each piston-wheel 38 extends into its correspondingcombustion cylinder 14 through a radially disposed annular slot 40 inthe periphery of each cylinder casing 16. Slot 40 is disposed completelyaround the circumference of each casing 16 and provides access: forpiston-wheel 38 to annular combustion cylinder 14. At the inner edge ofeach piston-wheel 38 within its combustion cylinder 14 is mounted anarcuately shaped, or torus-like, combustion piston 42, having across-sectional shape which is the mirror image of, but slightly smallerthan, that of its cylinder 14 for rotation therein about thelongitudinal axis of drive shaft 20. The length of each combustionpiston 42 is desirably such that its innermost surface is exactlysemi-cylindrical.

As illustrated in FIGS. 14 and 15 combustion pistons 42, 42 may havevarious cross-sectional shapes and may be mounted on piston-wheels 38 inany suitable manner, the same being true of compression pistons 28.FIGS. 10-14 show a shape and construction for both the compression andcombustion pistons which is similar to that of each of the pistonshereinbefore referred to in connection with FIGS. I-6 in that thecrosssectional profile of each piston is semi-circular at the ends andhas a laterally elongated central portion. In the case of piston 28(FIGS. 10 and 11), a pair of arcuately elongated sections 41, 41 aremounted, one on each side of piston-wheel 26 by means of a row of bolts43, each of which extends transversely through both sections 41, 41 andthrough a peripheral segment 26.] on the circumference of annularpiston-wheel 26. Both ends of each bolt 43 are recessed within thesections 41, 41, so that they lie below the surfaces of the piston 28.Similarly, the combustion piston 42, portions of which are shown on anenlarged scale in FIGS. 12-14, has arcuate sections 41a mounted onopposite sides of the annular piston-wheel 38 to a segment 38.1 on theinner edge thereof.

The segments 26.1 and 38.1 of piston-wheels 26 and 38, respectively,extend circumferentially the same distances around their respectivepiston-wheels 26 and 38 as the piston-forming sections 41, 41a and areshaped the same as said sections at both ends. In addition, in order toprovide greater support for piston sections 41, 41a, segments 26.1 and38.1 are somewhat reduced in width in order to form arcuate shoulders26.2 and 38.2, respectively, on both sides of pistonwheels 26 and 38against which sections 41, 410 are rigidly held. As illustrated in FIGS.10, 12 and 13, the holes 43a in pistonwheels 26 and 38, through whichmounting bolts 43 extend, may be arcuately elongated, so that the pistonsections 41, 41a can be adjusted lengthwise. Such adjustment makes itpossible to shift the position of the piston-forming sections so thattheir ends are exactly flush with the corresponding ends of the mountingsegments 26.1 and 38.1 on piston-wheels 26 and 38, thereby providingbroad surfaces at the ends of the pistons 28 and 42 for cammingengagement with the chamber-forming valves in each cylinder as will bemore apparent hereinafter.

In another form of piston shown in FIG. IS, the two lateral sections 4141 of piston 42' are shown welded to the piston-wheel instead of boltedas in FIGS. 10-14. Furthermore, as illustrated only by way of example,the cross-sectional shapes of the pistons may differ. However, thecross-sectional shape of compression pistons 28, 28 for each engine isdesirably the same as that for its combustion pistons 42, 42.

The maximum width P (FIGS. 14 and 15) of combustion piston 42 should besubstantially greater than the width W of the piston-wheel 38 on whichit is mounted. Thus, since only the narrow width W of piston-wheel 38 isexposed to the pressures developed within the combustion cylinder 14,the total force exerted in a radial direction on rotor 24 is relativelysmall. Consequently, problems of counteracting or balancing the forceson rotor 24 in order to reduce vibration, bearing wear and friction arenot as critical as in rotary internal combustion engines of most priordesigns. Furthermore, and of even greater importance, the provision ofannual rotary pistons ensures that most of the force resulting fromcombustion of the fuel is exerted tangentially of the rotor at a fixeddistance from the center of rotation, thereby producing maximum torqueon shaft and contributing substantially to improvement in the efficiencyof this type of rotary engine as compared to other types of rotaryengines, as well as to reciprocating piston engines.

As best seen in the cross-sectional view of FIG. 3 through the section Aof the engine, the arcuate compression piston 28 and arcuate combustionpistion 42 are disposed diametrically opposite each other on rotor 24,so that their ends overlap. A pairof pressure passages 44 and 440 arealso provided diametrically opposite each other in the annular wall 47in cylinder casing 16 between cylinders 12 and 14. Each of pressurepassages 44, 44a is identical and is provided with a relatively smallinlet 46 (FIGS. 5 and 6) from the compression cylinder 12 and anenlarged outlet 48 to the combustion cylinder 14.

VALVE ARRANGEMENT OF EMBODIMENT SHOWN IN FIGS. 1-15 Pivotally mounteddownstream. i.e. in the direction of rotation illustrated by arrows R,of each inlet 46 within compression cylinder 12 is a compression valve50, 500, the free end 52 of which extends upstream for pivotal movementbetween a chamber-forming position (FIG. 6) and a passageclosingposition (FIG. 5). With piston 28 in the position shown in FIG. 3,compression valve 50 is disposed across cylinder 12 in itschamberforming position, its free end 52 extending upstream of its pivotshaft 54, by which it is pivotally mounted in the cylinder casing 16. Atthe same time valve 50a diametrically opposite is held by piston 28 inits passage-closing position.

As may be seen in FIG. 7, compression valve 50 is a rectangular member,the dimensions of which are greater than the correspondingcross-sectional dimensions of cylinder 12 (shown in phantom in FIG. 7),so that the marginal portions thereof rest on a rectangular valve-seat56 (FIGS. 5 and 6) completely surrounding, and obliquely disposed acrosscylinder 12, thereby forming within cylinder 12 a compression chamber 58upstream of valve 50 and an intake chamber 60 downstream thereof. Valve50a (FIG. 3), on the other hand, is shown in its passage-closingposition, in which it is completely retracted out of the path of piston28 within a rectangular recess 62 (FIG. 6) in the walls of cylinder 12adjacent thereto. In their passage-closing positions, valves 50, 50aseat against rectangular valve-seats 64 surrounding the openings 46 tothe pressure passages 44, 440. As best shown in FIG. 5, flat pie-shapedside walls 65 are formed parallel to each other on opposite sides ofcylinder 12 for sealing engagement with the sides of valves 50, 50a asthey swing from one position to the other.

Adjacent to, and upstream of, each combustion outlet 48, 48a frompressure passages 44, 44a to the combustion cylinder 14 is pivoted acombustion valve 68, 68a, which is secured to a pin 66, 66a pivotallymounted in cylinder casing 16 for movement between a chamber-formingposition across the combustion cylinder 14 and a passage-closingposition longitudinally thereof. Like compression valves 50, 50a, eachcombustion valve 68, 68a is rectangularly shaped and seats against arectangular valve-seat 70 in its chamberforming position, where it isdriven out of the path of piston 42 into a rectangular recess 72, 72asurrounding one of the enlarged outlets from pressure passages 44, 44a,respectively. Each of recesses 72, 72a is provided with a valve-seat 74surrounding the outlet with which each combustion valve 68, 68a seatswhen in its passageclosing position. Flat pie-shaped side walls 75 (FIG.5) are formed in cylinder 14 adjacent each valve 68, 68a for sealingengagement with the sides thereof as it swings between its twopositions. In the portion of cylinder 14 shown in FIG. 3 that ismomentarily not occupied by combustion piston 42, valve 68a is free toswing into its chamber-forming position where it separates the cylinder14 into a combustion chamber 76 downstream and an exhaust chamber 78upstream.

In order to prevent the compressed gases in compression chamber 58 ofcylinder 12 from leaking past valves 50, 50a, and causing loss ofcompression, each of valves 50, 50a is provided with resilient edgeseals along its outer end and side edges, as shown for the valve 50 inFIGS. 7-9. Thus, an elongated groove 50.1 is formed adjacent the outerend 52 of valve 50, the inner edge 50.2 of valve 50 being rounded inorder to facilitate lifting of valve 50 from its chamber-formingposition by the leading edge of piston 28. Groove 50.1 is rectangularlyshaped in cross-section and extends across the full width of the valveso that it opens at both side edges 50.3, 50.3 of the valve, therebypermitting removal and replacement of a sealing strip 50.4 through theopen ends of the groove.

The outer longitudinal edge of sealing strip 50.4 projects outward ofgroove 50.1 through a restricted opening in the edge 50.2, the innerportion of strip 50.4 being enlarged so that it cannot escape edgewisefrom groove 50.1. Groove 50.1 is deep enough to permit limited edgewisemovement of sealing strip 50.4 through the restricted opening of thegroove. A series of holes 50.5 are provided along the length of groove50.1, each hole extending from groove 50.1 above the sealing strip 50.4to the pressure side of valve 50. Thus, when valve 50 or 500 is in itschamber-forming position, as illustrated diagrammatically in FIG. 8,pressure in compression chamber 58 is exerted on the inner side ofsealing strip 50.4, forcing it outwardly against the valve-seat 56 inthe wall of cylinder 12. Likewise, seal 50.4 maintains sealingengagement with the inclined end 79 of compression piston 28 as thelatter cams each compression valve out of engagement with valve-seat 56,thereby ensuring a tight seal at all times between the compressionchamber 58 and intake chamber 60.

Grooves 50.6 and sealing strips 50.7, similar to the grooves 50.1 and50.4, are provided in both side edges 50.3 of valve 50 for sealing thesides of the valve with the side walls 65 of the cylinder. In this case,however, the seal is disposed perpendicular to the edge of the valveinstead of obliquely. Pressure holes 50.8 are provided to grooves 50.6from the pressure side of valve 50 so that the seals press more tightlyinto engagement with the valve-seat as the pressure within thecompression chamber increases.

In order to reduce friction while maintaining an adequate seal betweenvalve 50 and piston 28, an antifriction roller 51 is mounted on valve 50on the side that is adjacent to piston 28. Roller 51 is locatedcentrally of cylinder 12 near the outer end of the valve 50 within arecess in the surface of the valve, so that it projects outwardtherefrom for engagement with the leading end 79' of piston 28 whilepermitting seal 50.4 to remain in sealing engagement with the pistonuntil valve 50 reaches is passage-closing position. Roller 51 thenremains in contact with the narrow segment 26.1 of piston-wheel 26,thereby reudcin drag.

Combustion valves 68, 68a are provided with seals similar to those forvalves 50, 50a and with rollers 51 for reducing friction and drag oncombustion pistonwheel 38. Since the pressure in combustion chamber 76is relatively low at the time piston 42 starts to engage either ofvalves 68, 68a, the resistance of valves 68, 68a to movement out oftheir chamber-forming positions is not as great as that involved inmoving the compression valves 50, 50a to their passage-closingpositions. However, rollers 51 help reduce friction between valves 68,68a and piston 42 caused by the pressure in pressure passages 44, 44aduring the compression stroke. Moreover, seals should be provided alongthe lateral edges of valves 68, 68a for sealing engagement with the sidewalls 75 (FIG. of the valve chamher, as well as along its outer edge, inorder to prevent blowby both during the instant that each of the valvespivots into and out of its chamber-forming position and while it is inengagement with its valve-seat 70 during the combustion stroke.

It is also desirable to provide seals in the valveseats 64 and 70 at theinlet and outlet, respectively, of each pressure passage 44. Seals 64.1(FIGS. 5 and 6) may therefore be provided in grooves in the wall 47 ofthe cylinder casing around the inlet 46, and seals 70.1 around theoutlet 48, for engagement by vlaves 50 and 68, respectively, when intheir passage-closing positions. Seals 64.1 and 70.1 are similar indesign to the seals 50.4 on the compression and combustion valves, eachhaving pressure holes extending from the groove behind the inner edge ofthe sealing strip to the pressure chamber 44 so that the pressure withinchamber 44 forces the seals outward against the valve.

An important advantage of the present invention resides in the fact thatit is not as difficult to seal one chamber form the other as in priorrotary engines because friction and wear due to movement of the rotoragainst the seals can be greatly reduced. In the first place, if anyseals at all are required between the pis' tons and the walls of thecylinders within which they revolve, they are not subjected to thepressure in the cylinder, because the pistons never actually engage thewalls of the cylinders. Furthermore, the great length of the pistonsthemselves will in most. cases make sealing of the pistons with thecylinders unnecessary.

The only other points at which seals must be made with moving parts arewhere the piston-wheels 26 and 38 extend into the cylinders and wherethe valves 50 and 68 must seal with the ends of the pistons during theshort periods when they are moved by the pistons to and from theirpassage-closing positions. As illustrated in FIG. 8, the seals 50.4 atthe outer ends of the valves engage the moving piston-wheels only alongthe relatively narrow circumferential edges: of the pistonwheels andalong the inclined ends of the pistons. Once each valve is in itspassage-closing position it is held by the piston against a stationaryvalve-seat, and no seal is required between the moving piston and thevalve.

In order to reduce wear of the seals as much as possible, it isdesirable to prevent the full force of the pressure on the valves in thecompression and combustion chambers from being exerted on seals 50.4while they are in contact with the piston-wheels. To this end, thecircular portion 26.4 on the periphery of piston-wheel 26 which isopposite its piston 28 is formed with a diameter that is somewhat lessthan that for the cylinder 12 at its inner diameter, so that thisportion of the periphery of the piston-wheel is recessed slightly inwardof cylinder 12, as illustrated in section A of the engine shown in FIG.4. In the case of the piston-wheel 38, the corresponding edge portion38.4 has a slightly greater diameter that the OD. of cylinder 14 so thatit is recessed outwardly thereof, as shown in section B of the engine.When valves 50 and 68 are seated against their chamber-formingvalve-seats 56 and 70, respectively, only their seals 50.4 (FIG. 8)touch the moving edges 26.4 and 38.4 of the corresponding piston-wheel.Consequently, all the pressure on each valve is exerted against thefixed valve-seat in the wall of the piston, rather than on the revolvingpiston-wheel. Seals 50.4 nevertheless are forced into engagement withthe piston-wheels by the pressure exerted on them by the gases throughpressure holes 50.5 in the opposite sides of the valves as describedhereinbefore, thereby providing the necessary seal with the edge of thepistonwheel.

Cylinders l2 and 14 are also provided with intake and exhaust ports bywhich a combustible fuel mixture is drawn into the intake chamber 60behind compression piston 28 and the exhaust gases are swept from theexhaust chamber 78 in front of combustion piston 42. To this end,compression cylinder 12 has a pair of intake ports 80, 800, each locatedimmediately downstream of its corresponding compression valve 50, 50a,so that as the trailing end of piston 28 passes each valve 50, 50a,permitting it to move into its chamberforming position, a gaseous fuelis drawn into the intake chamber' 60 from a suitable source, such as acarburetor (not shown). Similarly, combustion cylinder I4 is providedwith a pair of exhaust ports 82, 82a, each located immediately upstreamof its corresponding combustion valve 68, 680, so that as the trailingend of combustion piston 42 passes each valve 68, 68a, pen'nitting it tomove into its chamberforming position, the gases of combustion are sweptout of the exhaust chamber ahead of piston 42.

Referring in greater detail to the construction of cylinder casings l6,16 as shown more particularly in FIGS. 2 and 4, it will be seen thatcasing E6 of the section A of the engine is the same as thecorresponding casing in section B except that it faces in the oppositedirection. Each casing I6 is made up of two annular halves 84 and 86,which mate face to face along a parting line 88 (FIG. 4) through theannular wall 47 that separates cylinders I2 and 14 and is commontherewith. The mating surfaces along parting line 88 are desirablystepped as shown in FIG. 4 in order to ensure accurate alignment of thetwo halves 84 and 86, which are bolted together by means of a ring ofbolts 90 extending through wall 47.

Cylinders l2 and I4 are formed partly in one half 84 and partly in theother half 86 of easing I6. In addition, the inner slot 27 and outerslot 40, through which piston-wheel 26 and annular piston-wheel 38,respectively, extend radially into their corresponding cylinders l2 and14, are formed by radially inner and outer surfaces 92 and 94 on thehalf 84 and by radially inner and outer surfaces 96 and 98 on the otherhalf 86 which faces in the opposite direction. Both the facing surfaces92 and 96 and the facing surfaces 94 and 98 are precisely spaced fromeach other when the two halves 84 and 86 are bolted together in order toprovide close clearance tolerances on both sides of piston-wheels 26 and38. Suitable packing rings I and I02 (FIG. 4) are provided in annulargrooves in facing surfaces 92 and 96, respectively, on opposite sides ofpiston-wheel 26 in order to seal cylinder 12. Similar packing rings I04and 106 are provided on opposite sides of pistonwheel 38 for sealingcylinder 14.

During each revolution of rotor 24, pistons 28 and 42 pivot theirrespective valves 50, 50a and 68, 68a from the chamber-forming positionsinto the passage-closing positions and, therefore, are provided at theirleading ends with inclined surfaces which engage the valves and morethem positively into the recesses 62 and 72, respectively, where theyare completely out of the path of their respective pistons and are heldin sealing engagement with the passage-closing valve-seat by the pistonsthemselves. In order to facilitate movement of the compression valves50, 50a into their passageclosing positions, the leading end 79 ofcompression piston 28 is gradually inclined inwardly toward its tip 108.Counterclockwise rotation of piston 28 as viewed in FIG. 3 causes itsleading end 79 to move successively into engagement with the roundededge 50.2 (FIG. 8) at the free end 52 of each compression valve 50, 50aand to lift it outward to its passage-closing position. It should benoted, however, that before the inclined portion of piston 28 actuallyengages valve 50, the outer end 52 of the valve is engaged from below(see FIG. 8) by the sloping portion of the edge of piston-wheel 26 whereits reduced-diameter section 26.4 merges with the piston-mountingsegment 261. Movement of valve 50 out of engagement with its valve-seat56 is facilitated in this manner.

Similarly, the leading end of combustion piston 42 is gradually inclinedwith respect to the path of the piston, but in this instance surface 110is inclined outwardly towards its tip 112, so that the combustion pistonengages the free end 113, 113a (FIGS. 5 and 6) of each combustion valve68, 68a only at the extreme end of each exhaust stroke. Each of valves68, 68a is thus moved consecutively by combustion piston 42 into itspassage-closing position at the beginning of each combustion stroke. v

In order to still further reduce friction and wear between the valves 50and 68 and the surfaces of pistons 28 and 42, respectively, it isdesirable to extend the periphery of their respective piston-mountingsegments 26.1 and 38.] (FIGS. 11 and 14) slightly beyond the surfaces ofthe pistons, thereby forming circumferential ribs 26.3 and 38.3,respectively. A mating groove 114 (FIG. 4) in the outer wall of cylinder12 receives the rib 26.3 on piston 28, while a similar groove 115 in theinner wall of cylinder 14 receives rib 38.3 on piston 42.

As best seen in FIG. 5, when valves 50 and 68 are in theirpassage-closing positions, their anti-friction rollers 51 ride on therespective ribs 26.3 and 38.3 of pistons 28 and 42. Due to the fact thatthe ribs 26.3 and 38.3 are narrow, friction is virtually eliminated.Furthermore, these ribs may be hardened for longer wear. In the drawingsribs 26.3 and 38.3 are shown greatly exaggerated in height, it onlybeing necessary to lift the rollers 51 of valves 50 and 68 a slightdistance off the surface of the pistons 28 and 42, respectively.

It is desirable for ignition of the compressed charge to take placewithin each pressure chamber 44, 44a immediately after each compressionvalve 50, 50a is completely closed. Consequently, both the pressure dueto compression and the pressure of combustion are exerted against thecorresponding combustion valve 68 or 68a, forcing it out to itschamber-forming position across cylinder 14. The pressure of the burningfuel will of course be immediately exerted on the trailing end 116 ofcombustion piston 42 as it moves beyond the free end 113, 113a of eachof the combustion valves. In order to ensure almost instantaneousmovement of combustion valves 68, 68a to their chamber-formingpositions, and at the same time, to reduce energy losses by ensuringthat the gases of combustion exert as much pressure as possibletangentially of rotor 24, the trailing end 116 of combustion piston 42,unlike its leading end 110, is formed almost square with respect to thedirection of piston travel. However, in order to prevent damage tocombustion valves 68, 68a and to reduce noise as they are driven intotheir chamber-forming positions, it is desirable to provide theend-surface 116 with a short incline at the outermost side of piston 42,so that the valves are, comparatively speaking, gradually let off thepiston on to the valve-seats 70.

In addition, a shock-absorber or cushioning device 118 (shown more orless diagrammatically in FIG. 1) may be mounted on the pivot shaft 66 or66a of each combustion valve 68, 68a externally of cylinder casings l6,16 for cushioning their impact against the valveseats 70 as they arereleased by the piston 42. For example, each shockabsorber 118 mayconsist of a lever 120 fixed to one end of pivot shaft 66, whichprojects outward of casing 16. A dash-port 122 having a plunger 124 ismounted on the casing for engagement by the outer end of lever 120 suchthat clockwise movement of lever 120, as viewed in FIG. I, forcesplunger 124 inward. Valves 68, 68a are accordingly prevented fromengaging their chamber-forming valve-seats 70 with too great an impact,yet are provided freedom of movement in bothdirections at all othertimes. Where space within the cylinder casing permits, internalcushioning devices may be employed in place of the externalshock-absorbers 118. Such an internal device could be mounted, forexample, in the valveseats 70 in the walls of each combustion cylinderfor direct engagement by valves 68 or 68a.

While the displacement of cylinder 12 in comparison with the volume ofpressure passage 44 may e designed to provide a compression ratio thatis high enough to ignite diesel fuel due to the heat of compression, theengine here illustrated is assumed to be a gasoline engine and istherefore provided with two spark plugs 126 and 126a for each combustioncylinder. Each spark plug 126, 11260 is threaded through a suitableopening in the outer wall of cylindercasing 16 into each of the pressurepassages 44, 44a, and an ignition distributor (not shown) with leads toeach spark plug times the ignition of the compressed fuel just before orafter each combustion valve 68, 68a moves to its chamberformingposition.

An important feature of the present invention resides in the capabilityof both compression and combustion valves at both pressure passages 44,44a, to function almost simultaneously on completion of each compressionstroke of piston 28 and on ignition of the compressed charge in thepressure passage, without the provision of any external valve-actuatingmechanism. Thus, in the present embodiment of the invention as clearlyillustrated in the enlarged detail view of valves 50 and 68 shown inFIG. at the instant that compression is complete, the inclined surface79 at the leading end of compression piston 28 has cammed thecompression valve 50 upward into its passage-closing position, in whichit seals the inlet 46 to pressure passage 44. The trailing end H6 ofcombustion piston 42, on the other hand, is on the point of releasingcombustion valve 68, which is still in sealing engagement with theoutlet 48 to cylinder M from the pressure passage 44 and is underpressure from the compressed fuel therein. The opposite side of valve 68is exposed to the exhaust port 82 in cylinder I4 and is therefore underrelatively light pressure.

Ignition by means of spark plug 126 is desirably timed to take place atthe instant shown in FIG. 5 just before combustion valve 68 is releasedby piston 42, so that on release, it is driven by the expanding gases ofcombustion within passage 44 almost instantaneously into itschamberforming position against valve seat 70. Combustion then continuesand the expanding gases drive piston 42 through another one-halfrevolution where the same interaction between valves 50a and 68a takesplace to initiate another power stroke during the next half revolution.The companion cylinders and pistons in section B of the engine are atthe same time operating in the same manner as those of section A but 180out of phase therewith, so that as one power stroke in section A isbeing completed another in section B is starting, thereby not onlymaintaining power throughout each revolution, but also balancing theforces exerted on the rotor.

Any desired ratio of the volumes of the compression cylinder to thecombustion cylinder can be obtained by proper selection of thecross-sectional dimensions and lengths of the pistons. Likewise, thedistance required for valves 50, 50a and 68, 68a to move between theirpassage-closing position and chamber-forming position can be reduced bydecreasing the cross-sectional dimension H (FIG. I4) of the pistons andcylinders in a radial direction, while increasing their width P in orderto obtain the desired displacement. This is especially important inconnection with the combustion cylinder 14 and valves 68, 68a in orderto prevent loss of cylinder pressure due to possible blowby past thecombustion valve before it seals with its chamber-forming seat 70.

FIG. 6 is a view showing the condition of valves 50 and 68 afterone-half of a revolution of pistons 28 and 42 from the position in whichthey are shown in FIG. 5. Piston 42 completes each exhaust stroke as itsleading end engages valve 68 camming it into passageclosing position andsealing the outlet 48 from passage 44. Shortly after outlet 48 is sealedoff by valve 68, compression valve 50 pivots toward its chamberformingposition, in which it is shown in FIG. 6, as the trailing end I28 ofpiston 28 moves past, thereby opening the inlet 46 to passage 44. Atthis point a pressure differential exists on opposite sides of valve 50due to residual pressure in passage 44 from the just completed powerstroke and the partial vacuum in cylinder 12 from the intake stroke. Thecompression valve therefore follows the inclined end surface 128 ofpiston 28 into its chamber-forming position. If desired, a simpleextension spring (not shown) or other suitable means for urging valve 50toward its chamber-forming position may be provided. However, where suchspring means is provided, the force required to overcome it should belight, so that the resistance of the compression valve to movement inthe opposite direction by piston 28 to its passage-closing position isnot substantially increased.

From the foregoing it will be apparent that each compression valve formsa fixed wall of the combustion chamber when such valve is held in itspassage-closing position by the compression piston. On the other hand,when the compression valve is in its chamber-forming position it forms awall of the compression chamber with the pressure in the compressionchamber forcing the compression valve into sealing engagement with itschamber-forming valve-seat. Similarly, each of the combustion valves inits passage-closing position forms another wall of the compressionchamber, and in its chamber-forming position forms a wall of thecombustion chamber. Each set of valves, therefore function alternatelyto form a compression chamber and then a combustion chamber, theiraction being synchronized entirely by, and dependent upon, the rotarymovement of the two pistons in companion compression and combustioncylinders. No independent means, such as a cam-shaft, is necessary inorder to synchronize the operation of the valves.

' Still another advantage of the present invention resides in itssimplicity of design and accessibility of its parts for repair orreplacement purposes. For example, each of the compression passages 44,44a and valve assemblies therefor may be made as a complete subassemblywhich can be installed and removed from the engine as a unit. Thus, asindicated generally in FIGS. 5 and 6, the pressure-passage 44 may beformed within a section 47a of the annular wall 47 common to cylinindersl2 and 14 or to the outside of casing 16.

It will be appreciated that two complete cycles of operations take placeduring each revolution of rotor 24 for each pair of companion cylinders12 and 14. In other words, during each revolution two power strokes thatextend over l80 of rotation each are provided in each section A and B ofthe engine here illustrated. Consequently, this power plant producesfour power strokes per revolution. In comparison, a four-cyclereciprocating engine must have eight cylinders to produce four powerstrokes for each revolution. The rotary engine of the present inventionaccordingly has the advantages of both a four-cycle engine and atwo-cycle engine without the disadvantages of either.

Furthermore, at any time during each revolution, except at the instantwhen each combustion valve 68, 68a shifts into its chamber-formingposition, all four phases required in a four-cycle engine are takingplace simultaneously. Thus, at the instant of operation shown in FIG. 3,while compression piston 28 is drawing a gaseous fuel-mixture intointake chamber 60 behind its trailing end 128, it is also compressingthe previous intake charge in the compression chamber 58 into theadjacent pressure passage 44. During this phase of the cycle compressionvalve 50 is disposed in its chamberforming position while combustionvalve 68 is held in its passage-closing position by combustion piston42. At the same time, combustion is taking place downstream ofcombustion valve 68a in combustion chamber 76, which is closed offthrough pressure passage 44a by compression valve 50a, which in turn isheld by piston 28 in its passage-closing position. Simultaneouslytherewith, the exhaust gases from the previous combustion stroke areswept from exhaust chamber 78 through exhaust outlet 82.

A novel feature of the present design, which can be employed to greatadvantage for the purpose of obtaining complete combustion of thefuel-mixture during the combustion phase of the Otto cycle is theprovision of one or more injection ports 130 (FIGS. 1 and 3) in eachhalf of the combustion cylinder 14 intermediate valves 68 and 68a.Injection ports 130, 130 make it possible to introduce oxygen or otherchemicals and catalysts into the combustion chamber 76 under pressure bysuitable means (not shown), in order to ensure continued and regeneratedcombustion of the partially burned gases throughout the power stroke. Inthis instance, each port 130 is desirably located closer to thedownstream one of valves 68, 680 than to the one upstream, so that ascombustion begins to dissapate during a later portion of each combustionstroke, renewed combustion can be obtained by injection of a requiredcomponent of combustion, in order to completely burn the available fuelas the trailing end 116 of the combustion piston moves beyond eachinjection port 130. Not only does this reduce harmful exhaust emissions,but also it increases the power generated by the engine. It will beappreciated, however, that other injection ports can be provided in anydesired sequence at various points along the combustion chamber and thatthe order in which additions are made during each combustion stroke canbe controlled by suitable external equipment (not shown).

SlDE-BY-SIDE CYLINDER ARRANGEMENT OF FIGS. 16-21 In the embodiment ofthe invention shown diagrammatically, as well as pictorially, in FIGS.16-21, the compression cylinder 212 and combustion cylinder 214 are thesame diameter radially of the drive shaft 220 and are disposedside-by-side axially thereof. The cylinder block or casing 210 forcylinders 212 and 214 may be constructed in various ways to facilitatemanufacture and assembly, the details of which are omitted for purposesof clarity. Casing 210, like that in the form of the inventionillustrated in FIGS. 1-6, is cylindrically shaped and has an enlargedcentral opening 223, in which is journaled a hub 232 of a cylindricalrotor assembly 224.

Rotor assembly 224 consists of the shaft 220, a pair of circularpiston-wheels 226, 226, each fixed rigidly a shaft 220 on opposite sidesof hub 232, an arcuate compression piston 228 within cylinder 212 and acombustion piston 242 within cylinder 214. Pistons 228 and 242 arerigidly mounted at the axially inner edges of a pair of cylindricallyshaped, piston-mounting rings 229 and 231, respectively, which extendinwardly toward each other from piston-wheels 226, 226 through annularslots 227 and 240, respectively, in the opposite end walls of thecylinder block 210. Seals 200 are provided on the inner and outer wallsof annular slots 227 and 240 in the block 210 in order to preventleakage around piston mounting rings 227 and 231.

Pistons 228 and 242 may be constructed and assembled on mounting rings229 and 231 in a manner similar to their counterparts shown in FIGS.11-15 of the previously described embodiment of the invention, exceptthat the long axis of each piston is disposed radially of the axis ofrotation instead of parallel to it. Mounting rings 229 and 231 also areformed so that their inner edges extend beyond the pistons into annulargrooves 213 and 215, respectively, within the re spective cylinders 212and 214. As in the embodiment of FIGS. 1-6, pistons 228 and 242 aredisposed endfor-end in staggered relation to each other at diametricallyopposite portions of their respective cylinders, each piston occupyingsubstantially half the length of its annular cylinder.

While independent compression and chamber valves similar to thoseemployed in the embodiment of FIGS. l-6 may be used in the side-by-sidearrangement of the dual-cylinder power plant illustrated in FIGS. 16-21,it has been found that transfer of the compressed fuel mixture from thecompression cylinder to the combustion cylinder may be facilitated incertain instances by providing a unitary valve assemblage in place ofthe independent valves and 68, hereinbefore described for controllingthe flow of the fuel between the two cylinders. Thus, as illustrated inFIGS. 17-21 a pair of sliding valve-assemblies 245, 245a are disposeddiametrically opposite each other within the housing 210 each extendingradially across the full depth of the annular cylinders 212 and 214.Each of the identical valve assemblies 245 or 245a is a rigidrectangular sleeve guided within a rectangular passage 243, 243a incylinder block 210 for reciprocal movement across the two annularcylinders, i.e., parallel to shaft 220.

Each of the sliding valve assemblies 245, 245a includes two parallelside members which extend radially of, as well as obliquely to,cylinders 212, 214, such side members forming a pair of vane-type valves250 and 268 corresponding to the pivoted valves 50 and 68 of the enginedisclosed hereinbefore. Valves 250 and 268 are held in fixed relation toeach other by means of a radially inner side-panel 25l and a radiallyouter sidepanel 252, both said side-panels being secured to the innerand outer edges, respectively, of the valves 250 and 268 and formingtherewith the hereinbeforementioned rectangular sleeve characterizingeach of the sliding valve assemblies 245, 245a.

Compression valve 250 is disposed adjacent the compression cylinder 212and moves within the cross-over passage 243 between a chamber-formingposition shown in FIGS. l8-20 and a passage-closing position (FIG. 21Similarly, combustion valve 268 on the combustion side moves between itspassage-closing position (FIGS. 18-20) and chamber-forming position(FIG. 21). In order to prevent leakage, suitable valve seats areprovided similar to those for the valves 50 and 68 in the embodiment ofFIGS. l-6. In addition guide means for ensuring free movement of thevalve assemblies 245, 245a should likewise be provided. To this end, andby way of illustration only, the valve assemblies 245, 245a are shown inFIGS. 17 and as having radially projecting guide-ribs 253 adjacent bothends of the valves 250, 268. Guide-ribs 253 slide within correspondinggrooves 254 in the walls of the cylinder block. Seals 255 are readilyprovided between each of valve assemblies 245, 245a and its cross-overpassage in order to prevent the gases from leaking from the combustionchamber to the intake chamber and from the compression chamber to theexhaust chamber.

The engine operates in a manner similar to that of the first-describedunit shown in FIGS. l-6 insofar as each dual-cylinder assemblage isconcerned. Thus, at the point shown in FIG. 19, where the trailing endof piston 228 passes intake port 280 immediately after moving out ofengagement with the compression valve 250, valve assembly 245 is held inthe position shown in FIG. 19 by engagement of combustion piston 242with the combustion valve 268, thereby not only holding valve 268 in itspassageclosing position but also holding compression-valve 250 in itschamber-forming position. With continued rotation of the rotor 234 a newsupply of fuel mixture is drawn through port 280 into the intake chamberbehind piston 228, while the previous charge is being compressed aheadof piston 228 into the pressure chamber 244 formed between valves 250and 268 within valve assembly 245.

After one-half revolution of the rotor, the leading end of compressionpiston 228 cams the valve assembly 245 to its opposite position withinpassage 243 as illustrated in FIG. 21. Compression valve 250 is therebyshifted from its chamber-forming position to its passage-closingposition as combustion valve 268 moves into its chamber-forming positionso that the compressed charge of fuel gases are transferred to thecombustion chamber behind piston 242 in cylinder 214. With ignitiontaking place on completion of compression during the transfer of valveassembly 252 from one position to the other, piston 242 is drivenforward by the expanding products of combustion. Up-stream of combustionvalve 268, the exhaust gases are swept out 18 the exhaust port 282 bythe leading end of combustion piston 242.

It will be noted that in order to maintain sealing engagement betweenthe combustion valve and its piston and between the compression valveand its piston throughout the transfer of the compressed fuel mixture tothe combustion cylinder 214, the valve assembly 245 is positionedcontined between the sloping ends of the two pistons. The contour of thetrailing end of each piston must, therefore, correspond exactly with thecamming surface at the leading end of the other. While the trailing endof the combustion piston can not be as abrupt as the one in thearrangement of FIGS. 16, and slight energy loss that may result from theforces of combustion being erexted against a sloping surface on thepiston is more than compensated for by the advantages attained ingreatly reducing the force required to cam the compression valve 250from its chamberforming position or its passage-closing position ascompared to that required to cam compression valve 50 (FIGS. 5 and 6)through the same movement. This is due to the fact that in thevalve-actuating arrangement of FIGS. 16-21, the combustion valve 268moves simultaneously with the compression valve 250 and, therefore, nomatter how highly compressed the fuel is within the pressure chamber244, the resultant force of such pressure on the compression valve 250tending to maintain it in its chamber-forming position iscounterbalanced by the equal and opposite pressure on the combustionvalve 268. Consequently, the only force required to move the valveassembly 245 from the position in which it is shown in FIG. 49 to thatof FIG. 21 is the force necessary to overcome: resistance due toengagement of the valve assembly with the ends of the pistons and withthe housing in which it is guided.

VALVE ARRANGEMENT OF FIGS. 22-24 In the modified valve arrangement shownpurely diagrammatically in FIGS. 22-24, the annular compression andcombustion cylinders are disposed side-byside as in the embodimentillustrated in FIGS. 16-21. On the other hand, the valves are pivoted onthe engine housing similar to the manner in which they are mounted inthe embodiment of FIGS. 1-6. Thus, compression valve 350 is pivotallymounted downstream of a pressure passage 344 in the engine cylinderblock 310 for pivotal movement within the compression cylinder 312, andcombustion valve 368 is pivotally mounted upstream of the pressurepassage 344 for pivotal movement within the combustion cylinder 314.Valves 350 and 368, however, are connected by a link 369 such thatmovement by one through a portion of its total travel between itschamber-forming and passageclosing positions simultaneously results in aprecisely corresponding movement of the other valve. In this instancelink 369 is pivotally connected to both valve the the same distance fromtheir respective pivot axes. However, where the total travel of eachvalve differs, as for example where one cylinder is narrower than theother, the positions at which link 369 is connected to the valves mustbe adjusted accordingly.

FIG. 22 shows the compression piston 328 and combustion piston 342 inthe positions corresponding to the positions of pistons 228 and 242 inFIG. 19 and of pistons 28 and 42 of FIG. 6. Thus, combustion piston 342has just moved valve 368 into its passage-closing position, which inturn has moved to compression valve 350 into its chamber-formingposition, so that compression of the fuel mixture into passage 344 hasbegun.

FIG. 23 shows pistons 328 and 342 after they have made slightly lessthan one-half revolution from the position shown in FIG. 22. Piston 328has begun to move compression valve 350 off its chamber-forming seat andis driving the last of the charge of fuel mixture into passage 344.However, since the combustion valve 368 has begun to move off itspassage-closing seat permitting the fuel mixture to flow into theexpanding space behind the combustion piston 342, the compressed fuelmixture can be ignited as soon as the inclined cam surface on thecompression piston 358 that is exposed to the fuel mixture is equal to,or less than, exposed surface on the trailing end of combustion piston368.

FIG. 24 shows the compression valve 350 moved by piston 328 to itspassage-closing position and combustion valve 368 in its chamber-formingposition, ignition having taken place at the peak of compression. Theexhaust gases from the previous combustion cycle are starting to beforced out the exhaust port 382, as compression of the next charge offuel mixture starts on closing of the intake port 380.

It will be understood, that various combinations can be made of thearrangements illustrated in FIGS. 1-6, 16-21 and 22-2 4. For example,the unitary valve assembly of FIGS. 16-21 may be employed in aconcentric cylinder arrangement such as that shown in FIG. 3, or theindependently mounted valves of FIGS. 5 and 6 may be employed in anengine having the cylinders disposed side-by-side. Similarly, the valvearrangement of FIGS. 22-24 may be employed in place of the valves 50 andS8 of FIGS. 1-6 or in place of the valves 250 and 268 of FIGS. I6-2i.

What is claimed is:

I. In a rotary internal combustion engine having a casing, a rotorjournaled for rotation within said casing, at least one elongated,arcuately shaped compression piston rigidly mounted on said rotor forrotation within said casing for compressing a gaseous fuel mixture, atleast one elongated, arcuately shaped combustion piston rigidly mountedon said rotor in staggered relation to said compression piston forrotation within said casing and driven by combustion of a compressedcharge of fuel mixture, each of said pistons being equal in length interms of degrees of arc and extending through not substantially morethan 180 degrees of arc, said casing providing a compression spacewithin which said compression piston revolves and a combustion spacewithin which said combustion piston revolves, a pres sure passageinterconnecting said compression and combustion spaces and having aninlet from said compression space and an outlet to said combustionspace, said casing having an intake port opening into said compressionspace downstream of said inlet and an exhaust port opening from saidcombustion space upstream of said outlet,

the improvement comprising in combination,

a. a compression valve mounted on said casing adjacent said inlet formovement within said compression space into a chamber-forming positiondownstream of said inlet and dividing said compression space into acompression chamber upstream thereof and an intake chamber downstreamthereof such that upon rotation of said rotor said compression pistoncompresses a charge of said fuel mixture in said compression chamberinto said pressure passage while drawing another charge of fuel mixtureinto said intake chamber,

b. said compression piston having a surface at its leading end inclinedto its path of rotation for camming said compression valve out of itschamber-forming position upon rotation of the leading end of saidcompression piston into engagement with said compression valve,

c. a combustion valve mounted on said casing adjacent said outlet formovement within said combustion space into a chamber-forming positionupstream of said outlet and into a passage-closing position in which itcloses said outlet, said combustion valve in its chamber-formingposition being disposed such that it constitutes a wall of a combustionchamber downstream thereof and is urged by pressure in said combustionchamber into its chamber-forming position,

d. said combustion piston having a surface at its leading and inclinedto its path of rotation for camming said combustion valve into itspassageclosing position,

e. said combustion valve being held in its passageclosing position bysaid combustion piston for a portion of each revolution of said rotorcorresponding to the length of such piston,

f. said combustion valve in its passage-closing position constituting awall of said compression chamber, whereby upon movement of saidcombustion piston downstream thereof said combustion valve is releasedby said combustion piston so that it can move into its chamber-formingposition.

2. The combination defined in claim I, wherein said compression valve isadapted and arranged to be moved into a passage-closing position by saidcompression piston upon being cammed out of its chamberforming position,said compression valve being held by said compression piston in itspassage-closing position where it constitutes another wall of saidcombustion chamber for a portion of each revolution of said rotorcorresponding to the length of such piston.

3. The combination defined in claim 2, wherein said compression andcombustion spaces comprise separate annular cylinders defined withinsaid casing and which further includes a compression-chamber valve-seatformed transversely of said compression cylinder in the walls thereoffor sealing engagement with said compression valve when in itschamber-forming position,

and a combustion-chamber valve-seat formed transversely of saidcombustion cylinder in the walls thereof for sealing engagement withsaid combustion valve when in its chamber-forming position.

4. The combination defined in claim 3, wherein the trailing end of saidcombustion piston is disposed substantially radially of said annularcombustion cylinder and said pistons are disposed relative to each otherin a circumferential direction such that said compression valve iscammed into its passage-closing position while said combustion valve isheld in its passage-closing position and the trailing end of saidcombustion piston moves downstream of said combustion valve substantially instantaneously after said inlet is closed in order to releasesaid combustion valve so that it is driven into its passage-formingposition by the pressure of the gases within said pressure passage.

1. In a rotary internal combustion engine having a casing, a rotorjournaled for rotation within said casing, at least one elongated,arcuately shaped compression piston rigidly mounted on said rotor forrotation within said casing for compressing a gaseous fuel mixture, atleast one elongated, arcuately shaped combustion piston rigidly mountedon said rotor in staggered relation to said compression piston forrotation within said casing and driven by combustion of a compressedcharge of fuel mixture, each of said pistons being equal in length interms of degrees of arc and extending through not substantially morethan 180 degrees of arc, said casing providing a compression spacewithin which said compression piston revolves and a combustion spacewithin which said combustion piston revolves, a pressure passageinterconnecting said compression and combustion spaces and having aninlet from said compression space and an outlet to said combustionspace, said casing having an intake port opening into said compressionspace downstream of said inlet and an exhaust port opening from saidcombustion space upstream of said outlet, the improvement comprising incombination, a. a compression valve mounted on said casing adjacent saidinlet for movement within said compression space into a chamber-formingposition downstream of said inlet and dividing said compression spaceinto a compression chamber upstream thereof and an intaKe chamberdownstream thereof such that upon rotation of said rotor saidcompression piston compresses a charge of said fuel mixture in saidcompression chamber into said pressure passage while drawing anothercharge of fuel mixture into said intake chamber, b. said compressionpiston having a surface at its leading end inclined to its path ofrotation for camming said compression valve out of its chamber-formingposition upon rotation of the leading end of said compression pistoninto engagement with said compression valve, c. a combustion valvemounted on said casing adjacent said outlet for movement within saidcombustion space into a chamber-forming position upstream of said outletand into a passage-closing position in which it closes said outlet, saidcombustion valve in its chamber-forming position being disposed suchthat it constitutes a wall of a combustion chamber downstream thereofand is urged by pressure in said combustion chamber into itschamber-forming position, d. said combustion piston having a surface atits leading and inclined to its path of rotation for camming saidcombustion valve into its passage-closing position, e. said combustionvalve being held in its passage-closing position by said combustionpiston for a portion of each revolution of said rotor corresponding tothe length of such piston, f. said combustion valve in itspassage-closing position constituting a wall of said compressionchamber, whereby upon movement of said combustion piston downstreamthereof said combustion valve is released by said combustion piston sothat it can move into its chamber-forming position.
 2. The combinationdefined in claim 1, wherein said compression valve is adapted andarranged to be moved into a passage-closing position by said compressionpiston upon being cammed out of its chamber-forming position, saidcompression valve being held by said compression piston in itspassage-closing position where it constitutes another wall of saidcombustion chamber for a portion of each revolution of said rotorcorresponding to the length of such piston.
 3. The combination definedin claim 2, wherein said compression and combustion spaces compriseseparate annular cylinders defined within said casing and which furtherincludes a compression-chamber valve-seat formed transversely of saidcompression cylinder in the walls thereof for sealing engagement withsaid compression valve when in its chamber-forming position, and acombustion-chamber valve-seat formed transversely of said combustioncylinder in the walls thereof for sealing engagement with saidcombustion valve when in its chamber-forming position.
 4. Thecombination defined in claim 3, wherein the trailing end of saidcombustion piston is disposed substantially radially of said annularcombustion cylinder and said pistons are disposed relative to each otherin a circumferential direction such that said compression valve iscammed into its passage-closing position while said combustion valve isheld in its passage-closing position and the trailing end of saidcombustion piston moves downstream of said combustion valvesubstantially instantaneously after said inlet is closed in order torelease said combustion valve so that it is driven into itspassage-forming position by the pressure of the gases within saidpressure passage.
 5. The combination defined in claim 3, wherein saidcylinder casing includes a wall common to both said cylinders and saidpressure passage is formed in said common wall, said inlet being formedin the compression-cylinder side of said common wall and said outletbeing an enlarged opening to said combustion cylinder directly oppositesaid inlet, said valves being pivotally mounted on said common wall onopposite sides thereof and said combustion valve having a free enddisposed downstream of said combustion cylinder when in itspassage-closing position.
 6. The combination defined in claim 5, whereinthe trailing end of said combustion piston is disposeD substantiallyradially of said annular combustion cylinder and said pistons aredisposed relative to each other in a circumferential direction such thatsaid compression valve is pivoted into its passage-closing positionwhile said combustion valve is held by said combustion piston in itspassage-closing position and the trailing end of said combustion pistonmoves downstream of the free end of said combustion valve substantiallyinstantaneously after said inlet is closed in order to release saidcombustion valve so that it is pivoted by the pressure within saidpressure passage into its passageforming position.
 7. The combinationdefined in claim 3, wherein said cylinders are disposed concentricallyof each other one within the other.
 8. The combination defined in claim4, wherein said cylinders are disposed concentrically of each other onewithin the other.
 9. The combination defined in claim 5, wherein saidcylinders are disposed concentrically of each other one within theother.
 10. The combination defined in claim 6, wherein said cylindersare disposed concentrically of each other one within the other.
 11. Thecombination defined in claim 7, wherein said compression cylinder is theinner one of said concentric cylinders.
 12. The combination defined inclaim 3, wherein said cylinders are disposed side-by-side axially ofsaid rotor,
 13. The combination defined in claim 4, wherein saidcylinders are disposed side-by-side axially of said rotor.
 14. Thecombination defined in claim 5, wherein said cylinders are disposedside-by-side axially of said rotor.
 15. The combination defined in claim6, wherein said cylinders are disposed side-by-side axially of saidrotor.
 16. The combination defined in claim 5, wherein said common wallis provided with a removable wall-section, said pressure passage beingformed in said wall-section and said valves being mounted on saidwall-section such that said wall-section and valves together comprise asubassembly of said engine which is removable as a unit for cleaning,repair or replacement.
 17. The combination defined in claim 6, whereinsaid common wall is provided with a removable wall-section, saidpressure passage being formed in said wall-section and said valves beingmounted on said wall-section such that said wall-section and valvestogether comprise a subassembly of said engine which is removable as aunit for cleaning, repair or replacement.
 18. The combination defined inclaim 3, which includes a plurality of said pressure passages eachhaving a said inlet and a said outlet, said inlets being spaced equallyfrom each other along said compression cylinder and said outlets beingspaced equally from each other along said combustion cylinder, and whichfurther includes one of said compression and one of said combustionvalves for each of said pressure passages, said pistons beingsubstantially equal in length to the intervals between said inlets andoutlets, respectively.
 19. The combination defined in claim 4, whichincludes a plurality of said pressure passages each having a said inletand a said outlet, said inlets being spaced equally from each otheralong said compression cylinder and said outlets being spaced equallyfrom each other along said combustion cylinder, and which furtherincludes one of said compression and one of said combustion valves foreach of said pressure passages, said pistons being substantially equalin length to the intervals between said inlets and outlets,respectively.
 20. The combination defined in claim 5, which includes aplurality of said pressure passages each having a said inlet and a saidoutlet, said inlets being spaced equally from each other along saidcompression cylinder and said outlets being spaced equally from eachother along said combustion cylinder, and which further includes one ofsaid compression and one of said combustion valves for each of saidpressure passages, said pistons being substantially equal in length tothe intervals between saId inlets and outlets, respectively.
 21. Thecombination defined in claim 6, which includes a plurality of saidpressure passages each having a said inlet and a said outlet, saidinlets being spaced equally from each other along said compressioncylinder and said outlets being spaced equally from each other alongsaid combustion cylinder, and which further includes one of saidcompression and one of said combustion valves for each of said pressurepassages, said pistons being substantially equal in length to theintervals between said inlets and outlets, respectively.
 22. Thecombination defined in claim 3, wherein said combustion cylinder isprovided with an injection port for introducing a charge ofcombustion-regenerating material directly into said combustion chamberfor burning the products of combustion therein.
 23. The combinationdefined in claim 4, wherein said combustion cylinder is provided with aninjection port for introducing a charge of combustion-regeneratingmaterial directly into said combustion chamber for burning the productsof combustion therein.
 24. The combination defined in claim 5, whereinsaid combustion cylinder is provided with an injection port forintroducing a charge of combustion-regenerating material directly intosaid combustion chamber for burning the products of combustion therein.25. The combination defined in claim 6, wherein said combustion cylinderis provided with an injection port for introducing a charge ofcombustion-regenerating material directly into said combustion chamberfor burning the products of combustion therein.
 26. The combinationdefined in claim 3, which includes means for connecting said compressionand combustion valves, said connecting means and valves forming a valveassembly in which said valves move in unison, each of said pistonshaving a surface at its trailing end corresponding exactly with saidsurface at the leading end of the adjacent one of said pistons in theother cylinder and each of said trailing ends being positioned withrespect to the leading end of said adjacent piston such that engagementis maintained between each of said pistons and the corresponding one ofsaid valves as said valves are moved from one position to the other. 27.The combination defined in claim 26, wherein said cylinder casingincludes a wall common to both said cylinders, said inlet being formedin the compression-cylinder side of said common wall and said outletopening into said combustion cylinder on the side of said common walldirectly opposite said inlet, said valve assembly comprising a rigidmember slidably mounted within said common wall, said valves comprisingoppositely disposed side-walls of said valve assembly which extendobliquely to said annular cylinders and said connecting means comprisingrigid sidepanels of said valve assembly with said pressure passageformed between said side-walls and said side-panels within said valveassembly, and guide means within said common wall for slidably receivingsaid valve assembly for reciprocal movement between fixed limits,whereby in one of such limits of movement of said valve assembly saidcompression valve is disposed in sealing engagement with itscompressionchamber valve-seat and said combustion valve is disposed insealing engagement with said outlet, while in the other limit ofmovement of said valve assembly said compression valve is disposed insealing engagement with said inlet while said combustion valve isdisposed in sealing engagement with said combustion-chamber valve-seat.28. The combination defined in claim 5, which includes a link pivotallyconnecting said compression and combustion valves such that said valvesmove in unison, each of said pistons having a surface at its trailingend corresponding exactly with said surface at the leading end of theadjacent one of said pistons in the other cylinder and each of saidtrailing ends being positioned with respect to the leading end of saidadjacent piston such that engagement is maiNtained between each of saidpistons and the corresponding one of said valves as said valves aremoved from one position to the other.
 29. The combination defined inclaim 26, wherein said cylinder casing includes a wall common to bothsaid cylinders and having a removable wall-section, said pressurepassage being disposed within said wall-section with said inlet in thecompression-cylinder side thereof and said outlet opening into saidcombustion cylinder on the side of said wall-section directly oppositesaid inlet such that said wall-section and valve assembly comprise asubassembly of said engine which is removable as a unit for cleaning,repair or replacement.
 30. A valve for a rotary-piston type of machine,such as an engine or air compressor, such machine having a cylinderblock forming an annular cylinder, an annular piston rotatably mountedtherein and a pressure passage formed within said cylinder block havingan opening into said cylinder, said valve being adapted and arranged formounting within said cylinder block for reciprocation between achamber-forming position and a passage-closing position and having awall portion capable of dividing said annular cylinder circumferentiallyinto separate chambers on opposite sides of said wall portion when saidvalve is disposed in its said chamber-forming position, said wallportion being so disposed as to be positively moved by said piston fromits said chamber-forming position in said cylinder into engagement withthe opening to said passage in order to seal said passage from saidcylinder.